Process for the preparation of alpha-monochlorohydrin monoesters of carboxylic acids



United States Patent ()filice 3,3Zl,500 Patented May 23, 1967 3,321,500 PROCESS FOR THE PREPARATION OF a-MONO- CHLORGHYDRIN MONOESTERS OF CARBOX- YLIC ACEDS Ewald Katzschmann, Dortmund-Kruckel, Germany, assignor to Chemische Werke Witten G.m.b.H., Witter: (Ruhr), Germany N Drawing. Filed Oct. 20, 1964, Ser. No. 405,265 Oct. 22, 1963,

Claims priority, application Germany,

C 31,203 9 Claims. (Cl. 260-408) The present invention relates to ethylene glycol monoesters. More particularly, it relates to a-monochlorohydrin monoesters of carboxylic acids. Even more particularly, the invention relates to an improved process for the preparation of :x-monochlorohydrin monoesters of saturated aliphatic and aromatic carboxylic acids.

It is known that ethylene glycol monoesters may be prepared from saturated carboxylic acids, either alone or in mixture with each other, and ethylene oxide. Stoichiometric or excess quantities of ethylene oxide may be used. According to such known processes, the reaction is carried out in the absence of catalysts at temperatures of from 25 to 200 C., preferably between 80 and 160 C., and in the presence of a mixture of water and neutral inorganic alkali metal salts, such as chlorides and/ or nitrates and/ or sulfates. Amounts of up to 40% by weight, based on the amount of saturated carboxylic acid employed, of the inorganic alkali metal salts are used in these processes.

One of the objects of the present invention is to provide an improved process for the preparation of ethylene glycol monoesters, specifically a-monochlorohydrin monoesters of saturated aliphatic and aromatic carboxylic acids, which overcomes the disadvantages and deficiencies of the prior art processes.

Another object of the present invention is to provide a process for the preparation of a-monocblorohydrin monoesters of saturated aliphatic and aromatic carboxylic acids which may be carried out in an efficacious and convenient manner.

A further object of the invention is to provide a process that yields cz-InOnOChlOIOhYdl'iIl monoesters of saturated aliphatic and aromatic canboxylic acids in high purity and good yield.

A still further object of the invention is to provide a process for the preparation of a-mon'ochlorohydrin monoesters of saturated aliphatic and aromatic cauboxylic acids which may be carried out easily and simply.

These and other objects of the present invention will become apparent to those skilled in the art from a reading of the following specification and claims.

In accordance with the present invention, it has been found that a-monochlorohydrin monoesters of saturated aliphatic and aromatic carboxylic acids may be produced more etlicaciously when utilizing the prior art method of operation described above by reacting such carboxylic acids with epichlorohydrin instead of with ethylene oxide.

Used as saturated aliphatic or aromatic monoand polycarboxylic acids in the method of the present invention may be, for example, aliphatic carboxylic acids containing 1 to 20.carbon atoms, benzene carboxylic acids such as the benzenetricarboxylic and benzenetetracarboxylic acids and the substitution products thereof, phthalic acids, naphthalic acid, and other acids equivalent to those mentioned herein for the above-defined specified purpose. The neutral inorganic alkali metal salts to be used herein are preferably potassium chloride, potassium sulfate, and potassium nitrate. These alkali metal salts should have a purity of at least the degree known as pure and should be free of by-products which exert catalytic side effects on epichlorohydrin, on the intermediate products or on the end products of the present invention. Condensation and saponification are examples of such undesirable catalytic side effects.

Instead of the aforementioned neutral inorganic alkali metal salts, the corresponding alkaline earth metal salts may be employed, if desired, as long as they are watersoluble and do not yield any difiicultly water-soluble salts during the reaction with the saturated carboxylic acids.

The reaction with epichlorohydrin in accordance with the present invention proceeds generally somewhat more slowly than the prior art reactions with ethylene oxide under comparable conditions. Due to the high boiling point of epichlorohydrin, however, the reaction velocity may be favorably increased by Working at slightly higher temperatures.

A modification of the process of this invention involves carrying out the reaction by using a molar deficiency of epichlorohydrin and distilling, filtering off or Washing out the excess acid from the end product.

The products produced according to the process of the present invention are valuable intermediate products for the preparation of plasticizers, resins, and lacquers, generally without any further specific purification thereof. Depending upon the type of acid component used, the end products may be distilled or recrystallized. Upon further reaction thereof, derivatives of glycerol are obtained.

The following examples are given merely for purposes of illustration and are not to be considered as limiting.

Example I A mixture of G. n-Caprylic acid 72 Distilled water 200 Potassium chloride 6 Epichlorohydrin 60 was combined at room temperature in a glass stirring vessel equipped with a reflux cooler. The mixture was heated to 60 C. within one hour While it was vigorously stirred. A sample of the uniformly stirred mixture yielded initially an acid number of 83. After 8 hours, the acid number of the mixture was 17 and after a total of 15 hours, it was 3.5. The monoester precipitated, while standing, as an oily under-layer which was mechani cally separated, neutralized while stirring with a few drops of an n/2 (0.5 normal) solution of caustic potash (potassium hydroxide) and finally washed. The product thus obtained was distilled under vacuum until it was free from water and epichlorohydrin. As final product, there was obtained 109 grams of crude monoester, which represented a 91.3% yield. The product had the following characterizing numbers:

Found Calculated Acid number Saponifieation number Hydroxyl i1umber Chlorine content, percent The monoester may be distilled and passes over as a water-clear slightly viscous and odorless liquid at between to 138 C. and 1.3 mm. Hg pressure.

were combined at room temperature in a glass stirring vessel equipped with a reflux cooler and heated to 85 C. within 3 hours. The solid/ aqueous suspension turned into an oil/ aqueous suspension. The initial acid number was calculated as 97. After conversion into the oily/ aqueous condition after 3 hours, the acid number found was 30. Stirring was continued for another 2 hours at 85 C. The acid number went down to 2.6. The product was separated mechanically into an oily and an aqueous phase. The aqueous phase can be used in further batches. The oily phase was washed twice with a little water and then rendered free of water and epichlorohydrin under vacuum. The yield of the crude product monoester was 222 grams, i.e., 97.2% of the theoretical yield. It displayed a saponification number of 489 (calculated as 492).

After distillation of the crude product, 192 grams of water-clear monoester, equivalent to 84% of the theoretical yield, were found. The distilled product had the following characterizing numbers:

Boiling range-150 to 153 C. at 0.9 mm. Hg

Found Calculated Acid number saponification number Hydroxyl number Chlorine content, percent Example 111 Epichlorohydrin, commercial 125 was heated to 120 C. in a V4A shaker autoclave (a noncorrosive, acid-resistant steel autoclave) from within one hour, further shaken at that temperature for 45 minutes, and removed from the autoclave after cooling to 54 C. The product separated while standing into an aqueous upper layer and a slightly turbid under-layer. After mechanical separation in a separating funnel, the substratum or under-layer was absorbed in acetone and then filtered and separated by distillation from acetone, a little water, and a little epichlorohydrin. As residue there remained a faintly yellowish colored viscous liquid which solidified into a paste-like substance after two days. Distillation or recrystallization of this product was impossible.

The crude product had a weight of 174 grams, representing 99% of the theoretical yield. It had the following characterizing numbers:

were combined at room temperature in a glass stirring vessel equipped with a reflux cooler and heated to 80 C. within minutes. The initial acid number was 125. After a total of 4 /2 hours, the acid number had dropped to 1.1. The product was cooled rapidly with stirring; the oily layer was mechanically separated in a separating funnel, rendered waterand epichlorohydrin-free under vacuum, and filtered over carbon. Obtained were 174 grams,

representing 96.4% of the theoretical yield of n-butyric acid-a-monochlorohydrin monoester having the following characterizing numbers:

Found Calculated Acid number 3.8 0 saponification number 617 620 Chlorine content, percent- 19. 3 19. 7

The ester can be distilled easily. It passes over at between 122 to 124 C. and at 14 mm. Hg pressure as a viscous water-clear liquid having a faint odor. This odor is not a butyric acid odor. After distillation, the following characterizing numbers were found for the product:

saponification number 620 Hydroxyl number 1 312 1 Calculated as 310.

was combined at room temperature in a stirring vessel equipped with a reflux cooler and heater to 90 C. within 17 minutes. After a total of 1.5 hours, the acid number was 0.2. The product consisted of an oily and an aqueous phase. The oily phase was mechanically separated and distilled. In addition to a preliminary run of 20 grams and a residue of 5 grams, 96 grams of o-chlorobenzoic acid-a-monochlorohydrin monoester, 77% of the theoretical yield, was obtained as the main fraction within a boiling range of between 151 and l52.5 C. at 0.7 mm. Hg pressure. The yield may be further increased by returning the preliminary run of the distillation and the residue to the reaction mixture. Another portion contains the aqueous phase which also can be returned thereto. The following characterizing numbers were found for the main fraction:

Found Calculated Acid number 0. 4 O saponification number 450 450 Hydroxyl number 225/228 225 Chlorine content, percent 28. 2 28. 5

A comparative experiment which was carried out without the addition of sodium chloride, but under otherwise completely identical conditions, yielded an acid number of 80 after 6 hours. An acid number of 83 had been calculated for the batch. From this result, it can be seen that a reaction has practically not taken place.

was combined at room temperature in a stirring vessel equipped with a reflux cooler and heated to 80 C. within 15 minutes. It was then maintained between 80 and 85 C. for 3 hours. The acid number was 7.7 after this latter reaction time. The oily layer was separated, washed Example VII A reaction batch of Benzoic acid, Sublimated 122 Water, distilled 300 Potassium sulfate, crystallized 8 Epichlorohydrin, commercial 110 was combined at room temperature in a stirring vessel equipped with a reflux cooler and heated to 90 C. within 15 minutes. The acid number was 22 after 7 hours. While stirring, neutralization was effected with an n/2 solution of caustic potash. The oily layer was mechanical- 1y separated, washed twice with a little Water, rendered Waterand epichlorohydrin-free under vacuum, and filtered over active carbon. A quantity of 167 grams of water-clear benzoic aCld-a-IIIOHOChIOIOhYClI'lII monoester having a saponification number of 520 (calculated as 522) was obtained as product.

Example VIII A mixture of G. Capric acid, about a 90% solution 86 Water, distilled 250 Potassium chloride, chemically pure Epichlorohydrin, commercial 55 was treated as indicated in Example VII. After a total reaction time of 1.5 hours, the acid number was 4.8. After further treatment as described in Example VH, 124 grams of monoester were obtained which had the following characterizing numbers:

Saponification number 1 435 Acid number 0.3 Chlorine content 2 13.8%

1 Calculated for C10 424. 2 Calculated for C102 13.4.

Example IX An initial mix of G. Terephthalic acid monomethyl ester 90 Water, distilled 350 Potassium chloride, chemically pure 10 Epichlorohydrin, commercial 60 was combined at room temperature in a cylindrical vessel equipped With a stirrer and a reflux cooler and heated to 90 C. within 30 minutes. After a total time of 3 /2 hours, the reaction mixture was stirred in the cold and neutralized, while intensively stirring, with a 20% solution of aqueous caustic potash, using phenolphthalein as indicator therefor. Suction was effected thereafter, washing with water carried out, and the solid constituents dried. Obtained were 94 grams, representing 69% of the theoretical yield of terephthalic acid monomethyl-amonochlorohydrin monoester having the following characterizing numbers:

The yield is dependent upon the intensity of stirring because the reaction product forms flocks and inclusions during the reaction.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention and all such modifications are intended to be included within the scope of the following claims.

I claim:

1. A process for the preparation of tit-monochlorohydrin monoesters of carboxylic acids which comprises reacting a carboxylic acid selected from the group consisting of saturated aliphatic and aromatic carboxylic acids with epichlorohydrin in the presence of water and an inorganic compound selected from the group consisting of neutral inorganic alkali metal salts and neutral Watersoluble inorganic alkaline earth metal salts.

2. The process of claim 1, wherein the reaction is carried out at a temperature of between 25 and 200 C.

3. The process of claim 1, wherein the reaction is carried out at a temperature of between and C.

4. The process of claim 1, wherein said inorganic compound is used in an amount of up to 40% 'by Weight, based on the weight of carboxylic acid employed.

5. The process of claim 1, wherein the neutral inorganic alkali metal salt is potassium chloride.

6. The process of claim 1, wherein the neutral inorganic alkali metal salt is potassium sulfate.

7. The process of claim 1, wherein the neutral inorganic alkali metal salt is potassium nitrate.

8. A process for the preparation of zit-monochlorohydrin monoesters of carboxylic acids which comprises reacting a carboxylic acid selected from the group consisting of saturated aliphatic and aromatic carboxylic acids with epichlorohydrin at a temperature of between 25 and 200 C. in the presence of water and up to 40% by weight, based on the Weight of carboxylic acid employed, of an inorganic compound selected from the group consisting of neutral inorganic alkali metal salts and neutral Watersoluble inorganic alkaline earth metal salts, and separating the resulting monoester product from the reaction mixture.

9. The process of claim 1, wherein the neutral inorganic alkali metal salt is sodium chloride.

References Cited by the Examiner UNITED STATES PATENTS ALEX MAZEL, Primary Examiner.

CHARLES B. PARKER, JOSEPH R. JILES, Examiners.

ANTON H. SUTTO, Assistant Examiner.

P. BRUST, HENRY 

1. A PROCESS FOR THE PREPARATION OF A-MONOCHLOROHYDRIN MONOESTERS OF CARBOXYLIC ACIDS WHICH COMPRISES REACTING A CARBOXYLIC ACID SELECTED FROM THE GROUP CONSISTING OF SATURATED ALIPHATIC AND AROMATIC CARBOXYLIC ACIDS WITH EPICHLOROHYDRIN IN THE PRESENCE OF WATER AND AN INORGANIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF NEUTRAL INORGANIC ALKALI METAL SALTS AND NEUTRAL WATERSOLUBLE INORGANIC ALKALINE EARTH METAL SALTS. 